Cannabaceae

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Eta Leonis
Location of η Leo (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 10h 07m 19.95186s[1]
Declination 16° 45′ 45.592″[1]
Apparent magnitude (V) 3.486[2]
Characteristics
Evolutionary stage Blue supergiant (blue loop)[3]
Spectral type A0 Ib[2]
U−B color index −0.206[2]
B−V color index −0.026[2]
Astrometry
Radial velocity (Rv)1.40[4] km/s
Proper motion (μ) RA: −2.80[1] mas/yr
Dec.: −1.82[1] mas/yr
Parallax (π)2.57 ± 0.16 mas[1]
Distance1,270 ± 80 ly
(390 ± 20 pc)
Absolute magnitude (MV)−5.54[3]
Details
Mass10[5] M☉
Radius47[3] R☉
Luminosity19,000[5] L☉
Surface gravity (log g)2.00[5] cgs
Temperature9,600[2] K
Metallicity−0.04[3]
Rotational velocity (v sin i)2[2] km/s
Age25[5] Myr
Other designations
η Leo, 30 Leonis, HR 3975, BD+17°2171, HD 87737, FK5 379, HIP 49583, SAO 98955, GC 13899
Database references
SIMBADdata

Eta Leonis (η Leo, η Leonis) is a third-magnitude blue supergiant star in the constellation Leo, about 1,270 light years away.

Properties

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Eta Leonis is a blue supergiant with the stellar classification A0Ib. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[6] Though its apparent magnitude is 3.5, making it a relatively dim star to the naked eye, it is nearly 20,000 times more luminous than the Sun, with an absolute magnitude of -5.60. The Hipparcos astrometric data has estimated the distance of Eta Leonis to be roughly 390 parsecs from Earth, or 1,270 light years away. It is believed to be in a blue loop phase.[3]

Eta Leonis is apparently a multiple star system, but the number of components and their separation is uncertain.[7]

References

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  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. ^ a b c d e f Firnstein, M.; Przybilla, N. (2012). "Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters". Astronomy & Astrophysics. 543: A80. arXiv:1207.0308. Bibcode:2012A&A...543A..80F. doi:10.1051/0004-6361/201219034. S2CID 54725386.
  3. ^ a b c d e Przybilla, N.; Butler, K.; Becker, S. R.; Kudritzki, R. P. (2006). "Quantitative spectroscopy of BA-type supergiants". Astronomy and Astrophysics. 445 (3): 1099. arXiv:astro-ph/0509669. Bibcode:2006A&A...445.1099P. doi:10.1051/0004-6361:20053832. S2CID 118953817.
  4. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  5. ^ a b c d Tanrıverdi, Taner (2013). "Elemental abundances of the supergiant stars σ Cygnus and η Leonis". New Astronomy. 25: 50. arXiv:1512.04557. Bibcode:2013NewA...25...50T. doi:10.1016/j.newast.2013.03.013. S2CID 118525375.
  6. ^ Garrison, R. F. (December 1993). "Anchor Points for the MK System of Spectral Classification". Bulletin of the American Astronomical Society. 25: 1319. Bibcode:1993AAS...183.1710G.
  7. ^ Mason, Brian D. (1996). "ICCD Speckle Observations of Binary Stars.XV.An Investigation of Lunar Occultation Systems". The Astronomical Journal. 112: 2260. Bibcode:1996AJ....112.2260M. doi:10.1086/118179.
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source: https://en.wikipedia.org/wiki/Eta_Leonis

One thought on “Cannabaceae”

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

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